帮助解几道简算题第一题：81.5*15.8+81.5*51.8+67.6*18.5第二题：（9/20+6/7+15/16

81.5*15.8+81.5*51.8+67.6*18.5
=81.5(15.8+51.8)+67.6*18.5
=81.5*67.6+67.6*18.5
=67.6(81.5+18.5)
=67.6*100
=6760
（9/20+6/7+15/16）/（3/20+2/7+5/16）
=3(3/20+2/7+5/16)/(3/20+2/7+5/16)
=3
1993*1994-1/1993+1992*1994
=1994(1993+1992)-1/1993
=7946090-1/1993
=15836557369/1993

1.81.5*15.8+81.5*51.8+67.6*18.5=81.5*(15.8+51.8)+67.6*18.5=67.6*(81.5+18.5)=676
2.(9/20+6/7+15/16)/(3/20+2/7+5/16)=3(3/20+2/7+5/16)/ (3/20+2/7+5/16)=3
3。？

1,=81.5*(15.8+51.8)+67.6*18.5
=81.5*67.6+67.6*18.5
=67.6(81.5+18.5)
=67.6*100
=6760
2,